1. Field of the Invention
The present invention relates to apparatus and a process for the control of the warping speed in direct warping, in which: the actual value of the thread speed is determined and compared with the desired value; and, in dependence upon the control deviation, the driven speed of the warp beam is decreased with increasing winding diameter.
2. Discussion of the Relevant Art
As is disclosed in the reprint from "Kettenwirk-praxis", issue 3/81 published by applicant's assignee, it is known to provide a roller in front of the warp beam around which the warp thread is turned. This roller is provided with a tachometer and its output potential is utilized as a measure of the actual value of the thread speed. In this manner, the warping speed can be determined with an accuracy with .+-.1%. However, since such a roller is driven by frictional forces, a rather substantial burden is placed on the warp thread. Furthermore, during the start-up and braking stages, the control arrangement is influenced by slippage which occurs between the roller and the warp thread.
Accordingly there is a need for an improved apparatus and process of the foregoing type for providing better control of the warp speed without mechanically influencing the warp thread.